Pyrolized coal has an activated surface and tends to bond with oxygen. Accordingly, when the coal is stored as it is, heat generated by reaction with oxygen in air may cause the coal to spontaneously combust. In view of this, for example, in Patent Literatures 1, 2 listed below and the like, coal subjected to pyrolysis (300° C. to 500° C.) is cooled and then subjected to coal deactivation processing in which oxygen is adsorbed to the coal by exposing the coal to a processing gas atmosphere (100° C. to 200° C.) containing oxygen. Spontaneous combustion of upgraded coal in storage can be thus prevented.